iOS核心动画高级技巧之图层变换和专用图层(二)

iOS核心动画高级技巧之CALayer(一)

iOS核心动画高级技巧之图层变换和专用图层(二)
iOS核心动画高级技巧之核心动画(三)
iOS核心动画高级技巧之性能(四)
iOS核心动画高级技巧之动画总结(五)

　　仿射变换

　　iOS仿射变换是CGAffineTransform,仿射变换的特点是变换后的图形对边依然是平行的,它包括 CGAffineTransformMakeRotation(CGFloat angle) / CGAffineTransformMakeScale(CGFloat sx, CGFloat sy) / CGAffineTransformMakeTranslation(CGFloat tx, CGFloat ty),直接看代码

 blueView = UIView()
 blueView.frame = CGRectMake(, , , )
 blueView.backgroundColor = UIColor.blueColor()
 self.view.addSubview(blueView)

 yellowView = UIView()
 yellowView.frame = CGRectMake( +  / 1.414, , , )//注意yellowView的水平位置,和blueView作对比
 yellowView.backgroundColor = UIColor.yellowColor()
 self.view.addSubview(yellowView)

 blueView.transform = CGAffineTransformIdentity  //初始化transform
 blueView.transform = CGAffineTransformMakeScale(0.5, 0.5 )  //缩小0.5倍
 blueView.transform = CGAffineTransformRotate(blueView.transform, CGFloat(M_PI_4))   //旋转pi/4
 blueView.transform = CGAffineTransformTranslate(blueView.transform, , ) //平移400

 　　这里只需要注意transform的叠加互相之间是有影响的,blueView缩小了0.5倍和旋转了45°,所以本来应该在水平位置上平移400的最后在45°方向平移了200,所以在水平方向平移的距离大约是200/1.414,和yellowView形成对比.

　　3D变换

　　3D变换和仿射变换不同,虽然它也是乘以一个二维向量,但是它是4x4的二维向量,而仿射变换是2x3的向量,而且3D变换可以通过直接改变向量的单个的值来设置向量,比如transform.m11 / transform.m44 对应的就是向量上对应位置的值,由于是3维空间的变换,所以有些不同,仿射的旋转等价于3D变换的Z轴旋转,它的x,y的组合向量可以使它向倾斜的角度(如45°)旋转,而平移忽略掉Z轴上的就是一样的,缩放也是忽略掉Z轴上的就行.而由于是3D变换缩放会使平移缩放对应比例,而x/y/z轴的旋转都不会使它的方向改变,这是由于矩阵的值表示的范围广,不会互相影响.

 blueLayer.transform = CATransform3DIdentity  //初始化transform
 blueLayer.transform = CATransform3DMakeScale(0.5, 0.5, )  //缩小0.5倍
 blueLayer.transform = CATransform3DRotate(blueLayer.transform,CGFloat( M_PI_4 ), 0.0,  1.0, ) //旋转pi/4
 blueLayer.transform = CATransform3DTranslate(blueLayer.transform,, , )     //平移400

　　由于3D变换分成多个方向的,所以沿X或Y方向的旋转就像缩放了一样,可以通过设置向量对应的值来修复这个效果,让它看上去更真实一点,结果它会有一个倾斜角度,有一个投影效果,这样当你做平移的时候会改变显示的大小,所以一般不要一起用了,而要让这个效果有效,需要在初始化transform时就设置m34的值(这个值最好在-1/500.0 到 -1/5000.0之间),放到后面没有效果,在后面也不能用scale放大缩小,不然会覆盖这个值.所以这个效果基本是单独拿出来显示效果的.

 var transform = CATransform3DIdentity //初始化transform
 transform.m34 = - / 500.0 //设置m34的值
 // transform = CATransform3DScale( transform, 0.5, 0.5, 0) //缩小0.5倍,这里不能用
 transform = CATransform3DRotate(transform,CGFloat( M_PI_4 ), 0.0,  1.0, ) //旋转pi/4
 transform = CATransform3DTranslate(transform,, , )     //平移400
 blueLayer.transform = transform

　　当你在投射的方向平移足够大的距离,它最后的成像就是一个点了,这个点一般是图层的anchorPoint点,如果是一个图层的好几个子图层都需要这种效果,那么直接设置它的父图层transform的m34为-1/ 500.0 然后设置它的sublayerTransform属性,当设置它的子layer的rotote属性那个子layer就会有对应的投射效果. 如:outLayer.sublayerTransform = outLayer.transform

　　如果旋转180°从背面去看layer,layer会显示出和layer对称的的图片,因为layer是双面绘制的,但如果有文字就会看起来很混乱并且浪费GPU资源,所以最好能够禁用它,而layer提供了这个属性:doubleSided,值为true双面为false则为单面.

　　内外层layer的选择可以相互叠加和抵消,这个在Z轴上的旋转是可以的,但是在X/Y上并不是这样的,是由于它们并不处于同一个3D空间内,同时需要注意的是,如果使用m34这个特殊的向量值做投影,每次先给一个transform初始化为CATransform3DIdentity,然后直接设置m34的值然后做旋转等,再赋值给layer的transform

　　专用图层

CAShapeLayer

　　CAShapeLayer 是专门用来绘画形状的layer,它对比画图有很大的优势,它使用了硬件加速,所以绘图速度很快,它不需要寄宿图片所以不会使用太多内存,它也不会和普通图层一样被裁剪掉,而且它不会被像素化,最后就不会模糊.你可以设置lineWith（线宽，用点表示单位）/ lineCap（线条结尾的样子）和lineJoin（线条之间的结合点的样子）,但是只有一次设置的机会.CAShapeLayer还可以单独设置圆角,下面是代码和对应的两个运行效果,前面一个线条的人另一个是3个圆角的直角矩形.

DEMO1:
 1 let shapePath = UIBezierPath()
 shapePath.moveToPoint(CGPointMake(, ))
 shapePath.addArcWithCenter(CGPointMake(, ), radius: , startAngle: , endAngle:CGFloat(  * M_PI ), clockwise: true)
 shapePath.moveToPoint(CGPointMake(, ))
 shapePath.addLineToPoint(CGPointMake(, ))
 shapePath.addLineToPoint(CGPointMake(, ))
 shapePath.moveToPoint(CGPointMake(, ))
 shapePath.addLineToPoint(CGPointMake(, ))
 shapePath.moveToPoint(CGPointMake(, ))
 shapePath.addLineToPoint(CGPointMake(, ))

 let shapeLayer = CAShapeLayer()
 shapeLayer.strokeColor = UIColor.redColor().CGColor
 shapeLayer.fillColor = UIColor.clearColor().CGColor
 shapeLayer.lineWidth =
 shapeLayer.lineJoin = kCALineJoinRound
 shapeLayer.lineCap = kCALineCapRound
 shapeLayer.path = shapePath.CGPath
 self.view.layer.addSublayer(shapeLayer)

DEMO2:
1 var rect = CGRectMake(, , , );
 var radii = CGSizeMake(, );
 var corners = UIRectCorner.TopRight | UIRectCorner.BottomRight | UIRectCorner.BottomLeft
 var shapePath = UIBezierPath(roundedRect: rect, byRoundingCorners: corners, cornerRadii: radii) 

CATextLayer

　　可以在layer中直接用Core Graphics直接写入文字,这就是UILabel的实现方式,如果直接在图层上记录文本将是一件很麻烦的事,iOS提供了CATextLayer来实现layer上显示文本,它本身使用了Core text ,渲染速度很快.

 var textLayer = CATextLayer()
 textLayer.frame = CGRectMake(, , , )
 self.view.layer.addSublayer(textLayer)

 //设置它的属性
 textLayer.foregroundColor = UIColor.redColor().CGColor
 textLayer.alignmentMode = kCAAlignmentJustified
 textLayer.wrapped = true

 //它的font是CGFont类型,需要大小字体分开设置
 var font = UIFont.systemFontOfSize()
 textLayer.font = CGFontCreateWithFontName(font.fontName)
 textLayer.fontSize = font.pointSize

 var textStr = "hello kitty hi nohhhh no wo  shi lllll aaaaawo  jiojhello kitty hi nohhhh no wo  shi lllll aaaaawo  jioj"
 textLayer.string = textStr

 //它contentScale默认是1,为了让它以retina的质量来显示,设置为2
 textLayer.contentsScale = UIScreen.mainScreen().scale

　　　这里也可以用NSAttributedString富文本,但是由于swift类型转换的问题挺麻烦的,不写demo了.

CATransformLayer

　　这个图层类解决了图层间的层级关系,如下面这个demo所示:如果是CALayer旋转就没有层级,如果是CATransformLayer,它就有了层级

 //outLayer = CALayer()
 outLayer = CATransformLayer() //如果是上面这个普通的CALayer它如果旋转就不会有双层的效果

 outLayer.frame = CGRectMake(, , , )
 outLayer.backgroundColor = UIColor.grayColor().CGColor
 self.view.layer.addSublayer(outLayer)

 var transform = CATransform3DIdentity //初始化transform
 transform.m34 = - / 500.0 //设置m34的值
 transform = CATransform3DRotate(transform,CGFloat( M_PI_2 ), 0.0,  1.0, ) //旋转pi/4
 outLayer.transform = transform

 //outLayer.sublayerTransform = transform

 blueLayer = CALayer()
 blueLayer.frame = CGRectMake(, , , )
 blueLayer.backgroundColor = UIColor.blueColor().CGColor
 outLayer.addSublayer(blueLayer)

 var blueLayerTransform = CATransform3DIdentity;
 blueLayerTransform  = CATransform3DTranslate(blueLayerTransform, , , );
 blueLayer.transform = blueLayerTransform;

 redLayer = CALayer()
 redLayer.frame = CGRectMake(, , , )
 redLayer.backgroundColor = UIColor.redColor().CGColor
 outLayer.addSublayer(redLayer)

 var fromValue = CATransform3DIdentity
 fromValue.m34 = - / 500.0
 fromValue = CATransform3DRotate(fromValue, , , , )

 var toValue = CATransform3DIdentity
 toValue.m34 = - / 500.0
 toValue = CATransform3DRotate(toValue, CGFloat( M_PI ), , , )

 var basicAnimation = CABasicAnimation(keyPath: "transform")
 basicAnimation.duration = 1.0
 basicAnimation.fromValue = NSValue(CATransform3D:fromValue)
 basicAnimation.toValue = NSValue(CATransform3D:toValue)
 outLayer.transform = toValue
 outLayer.addAnimation(basicAnimation, forKey: "transform3D")

CAGradientLayer

　　CAGradientLayer它主要是可以设置渐变色,通过colors属性和,startPoint和endPoint设置过渡颜色和位置,这时候设置背景色是没有用的

 gradientLayer = CAGradientLayer()
 gradientLayer.frame = CGRectMake(, , , )
 gradientLayer.backgroundColor = UIColor.grayColor().CGColor
 self.view.layer.addSublayer(gradientLayer)

 gradientLayer.colors = [UIColor.redColor().CGColor,UIColor.blueColor().CGColor, UIColor.greenColor().CGColor]
 gradientLayer.startPoint = CGPointMake(, )
 gradientLayer.endPoint = CGPointMake(, )

 　　它还有一个locations属性,可以设置每个渐变色的间距,这个数组的长度需要和colors数组的长度相同,location的值是按endPoint的值来说的,不是是多少及时多少

CAReplicatorLayer

　　CAReplicatorLayer可以使用在需要创建多个同样的layer只是轨迹颜色有规则的变化的时候,它会把它的子图层有规律的重复展示出来,而可以设置它重复的次数/每次渐变的颜色递增递减值/每次transform变换的路径.

 repeatLayer = CAReplicatorLayer()
 repeatLayer.frame = CGRectMake(, , , )
 repeatLayer.backgroundColor = UIColor.grayColor().CGColor
 self.view.layer.addSublayer(repeatLayer)

 var transform = CATransform3DIdentity
 transform = CATransform3DTranslate(transform, , , );
 transform = CATransform3DRotate(transform, CGFloat( M_PI / 5.0 ), , , );
 transform = CATransform3DTranslate(transform, , -, );
 repeatLayer.instanceTransform = transform;

 repeatLayer.instanceCount = 

 repeatLayer.instanceBlueOffset = -0.1
 repeatLayer.instanceRedOffset = -0.1

 var layer  = CALayer()
 layer.frame = CGRect(x: , y: , width: , height: )
 layer.backgroundColor = UIColor.whiteColor().CGColor
 repeatLayer.addSublayer(layer) 

　　它最后的结果就是一圈颜色递变的正方形,它可以做动画中一个飞机的路径等效果.它的一个重要实际用处就是做倒影,因为如果做图层的复制的话,倒影不可能跟着原layer做实时更新,而CAReplicatorLayer就可以做到.

 reflectionLayer = CAReplicatorLayer()
 var img = UIImage(named: "3333.jpg")
 reflectionLayer.frame = CGRectMake((self.view.bounds.size.width - img!.size.width) /  , , img!.size.width, img!.size.height * 1.5)
 reflectionLayer.backgroundColor = UIColor.grayColor().CGColor
 self.view.layer.addSublayer(reflectionLayer)

 var transform = CATransform3DIdentity
 transform = CATransform3DScale(transform, , -0.5, );
 transform = CATransform3DTranslate(transform, , -img!.size.height *  /  + , 0.0);
 reflectionLayer.instanceTransform = transform;

 reflectionLayer.instanceCount = 

 var imageLayer  = CALayer()
 imageLayer.frame = CGRect(x: , y: , width: img!.size.width, height: img!.size.height)
 imageLayer.backgroundColor = UIColor.whiteColor().CGColor
 imageLayer.contents = img!.CGImage
 //layer.anchorPoint = CGPointMake(0, 0)
 reflectionLayer.addSublayer(imageLayer)

 //设置透明度,在外面用个层来设置
 var gradientLayer = CAGradientLayer()
 gradientLayer.colors = [UIColor.whiteColor().colorWithAlphaComponent(0.2).CGColor, UIColor.whiteColor().CGColor]
 gradientLayer.frame = CGRectMake(reflectionLayer.frame.origin.x , reflectionLayer.frame.origin.y + reflectionLayer.frame.size.height / 3.0 * , reflectionLayer.frame.size.width, reflectionLayer.frame.size.height / )
 self.view.layer.addSublayer(gradientLayer)

 //设置文字
 var textLayer = CATextLayer()
 textLayer.frame = CGRectMake(, , , )
 self.view.layer.addSublayer(textLayer)

 //设置它的属性
 textLayer.foregroundColor = UIColor.redColor().CGColor
 textLayer.alignmentMode = kCAAlignmentJustified
 textLayer.wrapped = true

 //它的font是CGFont类型,需要大小字体分开设置
 var font = UIFont.systemFontOfSize()
 textLayer.font = CGFontCreateWithFontName(font.fontName)
 textLayer.fontSize = font.pointSize

 var textStr = "What a fuck!"
 textLayer.string = textStr

 //它contentScale默认是1,为了让它以retina的质量来显示,设置为2
 textLayer.contentsScale = UIScreen.mainScreen().scale

 imageLayer.addSublayer(textLayer)

 var basicAnimation = CABasicAnimation(keyPath: "position.y")
 basicAnimation.duration = 2.0
 basicAnimation.fromValue =  Float( textLayer.position.y  )
 var toValue:Float = Float( textLayer.position.y  + 100.0)
 basicAnimation.toValue = NSNumber(float: toValue)
 basicAnimation.removedOnCompletion = true
 basicAnimation.fillMode = kCAFillModeForwards
 textLayer.addAnimation(basicAnimation, forKey: nil)

 // textLayer.frame.origin.y = CGFloat( toValue)
 textLayer.position = CGPointMake(textLayer.position.x, textLayer.position.y  + 100.0)

CAScrollLayer

　　CAScrollLayer和UIScrollView类似,它和CALayer相比多了个scrollPoint的方法,如果要用这个方法可以使用CAScrollLayer

 NSTimer.scheduledTimerWithTimeInterval(, target: self, selector: NSSelectorFromString("setPosition"), userInfo: nil, repeats: false)

 func setPosition () {
     self.scrollLayer.scrollToPoint(CGPointMake(, ))
 }

CATiledLayer

　　CATiledLayer的可以做到图片/PDF等的分割显示,如果一个一张图片分辨率超过2048*2048(因平台不同),超过了OpenGL最大纹理尺寸,所以会有性能问题,一个PDF一般也比较大,所以容易出现性能问题(后面会单独写一个demo)

CAEmitterLayer

　　CAEmitterLayer能模仿粒子反射,如果火焰等,能控制粒子颜色/放射的速率,透明度,方向,个数等.

 emitterLayer = CAEmitterLayer()
 emitterLayer.frame = CGRectMake( , , , )
 emitterLayer.backgroundColor = UIColor.grayColor().CGColor
 self.view.layer.addSublayer(emitterLayer)

 emitterLayer.renderMode = kCAEmitterLayerAdditive
 emitterLayer.emitterPosition = CGPointMake(emitterLayer.frame.size.width / , emitterLayer.frame.size.height / )

 var cell = CAEmitterCell()
 cell.contents = UIImage(named: "lizi.png")?.CGImage
 cell.birthRate =  //粒子出现的速率
 cell.lifetime = 4.0 //声明周期,秒
 cell.emissionRange =  //发射的方向

 cell.color = UIColor(red: , green: , blue: 0.5, alpha: ).CGColor //粒子的颜色
 cell.alphaSpeed = -0.4 //透明度改变速率
 cell.velocity = //粒子运动速度
 cell.velocityRange = //粒子速度范围,约束速度

 emitterLayer.emitterCells = [cell]

CAEAGLLayer

　　它是一个提供用OpenGL ES来绘图的layer,它可以预先假设要绘制的类型,快速绘制,它可以配合GLKit中的CLKView使用,具体demo专门写.

AVFoundation

　　它是foundation框架里的,但是和layer的使用是一致的,demo如下

 var urlStr = NSBundle.mainBundle().pathForResource("1.mp4", ofType: nil)
 var url = NSURL(fileURLWithPath: urlStr!)
 var player = AVPlayer(URL: url)

 var playLayer = AVPlayerLayer(player: player)
 playLayer.frame = CGRectMake(, ,, )
 playLayer.backgroundColor = UIColor.grayColor().CGColor
 self.view.layer.addSublayer(playLayer)

 player.play()